1. Field of the Invention
The present invention relates to signature handling. Specifically, the present invention relates to a collator feeder for removing signatures from a stack in a hopper and delivering the signatures to a conveyor of the collator.
2. Description of the Prior Art
A feeder for removing signatures from a hopper and delivering the signatures to a collating conveyor is known. One known feeder includes a rotating drum having gripper mechanisms spaced circumferentially thereabout. A separating mechanism separates one signature from the bottom of the stack of signatures in the hopper. One of the gripper mechanisms removes the separated signature from the hopper as the drum rotates past the hopper. The gripper mechanism releases the signature after a predetermined amount of drum rotation to deliver the signature to the collating conveyor. This known feeder is limited in speed of operation because the gripper mechanism "yanks" the signature from a standstill from the hopper which tends to tear the signature if the drum is rotated at a relatively high speed.
Another type of feeder is disclosed in U.S. Pat. Nos. 3,552,740 and 2,903,260. These patents disclose rotatable drums each having a plurality of elongated rollers circumferentially spaced within the periphery of the drum. The longitudinal axes of the rollers extend parallel to the axis of rotation of the drum. The rollers are driven to rotate at a speed proportional to the speed of rotation of the drum and in an opposite direction. Each of the rollers has a gripper mechanism which removes a signature from a hopper as the drum rotates past the hopper. As the drum rotates past the hopper, the signature is "peeled" off the stack by the gripper mechanism and stored on the surface of the roller. Very little force is imparted to the signature by the gripper mechanism because the speed at which the roller rotates relative to the signature during drum rotation is low.
This type of feeder is limited in the speed at which it can operate because one signature must be completely removed from the hopper before the next signature can be removed. This results from a fixed arcuate distance existing between adjacent rollers about the drum.
In U.S. Pat. No. 4,127,262 another type of signature feeder is disclosed in which one signature is removed from the bottom of a stack of signatures while a second signature is starting to be removed. The apparatus delivers the signature to a transversely extending conveyor in a "shingled" arrangement. This apparatus is capable of signature removal at a relatively high rate. However, it is not adapted for use in a collator. Thus, improvements are needed to increase the speed at which signature feeding from a hopper can be accomplished.